Agricultural combine harvesters are machines designed for harvesting and processing crops such as wheat or corn. Crops are cut from the field on a wide area by the header mounted at the front of the combine. The harvested material is transported by a feeder to a pair of laterally or longitudinally mounted threshing rotors.
In Twin Rotor® type combine harvesters produced by the applicant, a Dynamic Feed Roll™ is mounted between the feeder and the longitudinally placed pair of threshing rotors. The DFR feeds the crops through to the threshing rotors while removing larger objects such as stones or wooden blocks. The DFR is an example of a rotating component liable to become blocked when large stones or swathes of densely packed crop material are transported through the feeder. Deblocking the DFR requires manual manipulation of the roll, for example rocking the roll back and forth a number of times. This manual intervention is cumbersome and time-consuming.
Other agricultural machines such as balers or forage harvesters are often also equipped with similar feed rolls which are susceptible to blocking and generally suffering from the same drawbacks as described above. Similar problems may occur in any type of work machine comprising rotating or otherwise moving components.
Systems have been devised for deblocking a rotating component with the help of a hydraulic actuator and a ratchet mechanism. An example of such a system applied in an agricultural baler is shown in document EP-A-1847170. However these mechanisms do not allow to reproduce the required back-and-forth rocking movement needed for effective deblocking.